| abstract |
[PROBLEMS] In a process in which compressed air and cement milk are jetted while rotating into the ground at an ultrahigh pressure by a jet grout method, and the ground is cut and mixed in a short time. 2) Ground improvement additive that satisfies the following requirements: 2) Reducing the amount of construction sludge generated by lowering the injection rate, and 3) ensuring the required early strength at the same time. And a ground improvement cement composition using the same. A ground for a jet grout method comprising the following A component and B component, and comprising a proportion of A component of 10 to 95% by mass and B component of 5 to 90% by mass (total of 100% by mass) Improved additive. Component A: Water-soluble vinyl copolymer having a weight average molecular weight of 2,000 to 50,000 obtained by alkaline hydrolysis of a copolymer of olefin having 3 to 8 carbon atoms and maleic anhydride Component B: selected from sodium sulfite and sodium nitrite At least one sodium salt selected [selection figure] None |